A one dimensional villain is a very boring villain indeed. Just being evil just for the sake of being be evil is so overused. I think it's because some creative choices some filmmakers make with villains is to make them unsympathetic so that you do hate them without feeling guilty about hating them.

characters can be flat out evil and still be interesting. There are A LOT of villains who are deep, those parts just go overshadowed.

thanos is my favorite villain, he's not relatable, and you don't sympathize with him, but I understand his point of view, and his intellect, and his perspective is why he's my favorite villain.

Villains are villains, and they don't have to be enjoyable, or even relatable for you to enjoy them.

Look at captain america and the red skull. The skull is evil and twisted and just a sick, sick man, as is norman osborne. They are awesome villains, and they aren't relatable. They represent true evil, especially the skull. He is the polar opposite of captain america and is one of marvel's best villains. Villains don't have to be relatable. Just because Loki in the movies has an understanding past (Which is incredibly argueable, to me it's pretty clear that in thor 1, he was ALREADY twisted), doesn't mean he isn;t evil, it just shows WHY he is evil.

I hope that he strays closer to comic book Loki. This movie is going to be big and I would prefer that characters are done as they should